1. Field of the Invention
The present invention relates to a miniaturized pressure sensor with a shell of an elastic material, an elastic diaphragm arranged over an opening situated in the surface of the shell, a light conductor arranged inside the shell, a silicon body arranged inside the shell and a reflecting surface arranged on the body such as to be opposite of the light conductor.
2. Description of the Related Art
A device of the kind mentioned above is known from Swedish patent specification 86 02836-2. There is still a need to further miniatures this known pressure transducer, but in attempting to do so problems occur which are directly related to the small dimensions.
The known pressure transducer is a so-called relative pressure transducer, which means that it measures the pressure difference between ambient pressure and a reference pressure. The reference pressure is in contact with the atmospheric pressure via an air duct inside the shell. This air duct has a constriction formed by a silicon body situated in the region of the diaphragm.
The problem with the known pressure transducer is that the resistance of the air duct to volume changes caused by the diaphragm moving is not sufficiently low, and for rapid pressure changes this leads to the occurrence of a certain excess pressure in the distal air volume nearest the diaphragm, this air volume being limited on one side by the constriction. This excess pressure falsifies the measuring result.